You’re sending the message to the Character Movement Component (which probably does not even implement said interface), not to the LB. You cannot send stuff like this to the LB. I think it’d work with streaming level, can’t recall - it should.
If you must script in the LB, obtain the reference to the Player who is generating the noise there. If the player is spawned dynamically, fetch it with Get Pawn / Character.
This is a better use case scenario for a basic dispatcher: